Config

Named sources describe provider intent, not host discovery. Every source is declared with Packages: none is implied, and a project whose environments have no tool of a package source declares none. Overlay inputs apply only where an environment selects them. Custom and Raw retain consumer-specific extension data.

A program that is downloaded rather than installed by a package source: its command name and a recipe, a function from a System to where the program is downloaded from there (see Download). The recipe is asked once for each declared System while the configuration is checked, and only its answers reach the Spec. An environment has the programs its Programs lists. One that several environments share is an ordinary binding, roc_stable = Fetch(...), or is inherited with Extend; the same name always means the same downloads.

What a recipe answers for one System. File(url) is the program itself. Archive(url, format, member) is an archive that is unpacked whole, with the program at the path member inside it. Mirrored(download, urls) is one of those two with alternate URLs for the same bytes, tried in order after its own, as in Mirrored(File("https://example.org/tool"), ["https://mirror.example.net/tool"]). Unavailable says the program does not exist for that System, which is an error only where a task needs it. A recipe that cannot answer at all, for a version it does not know, says so with crash: the compiler reports the message with the recipe's file and line.

Each text is checked as what it is where it is written: a Url is https://<host>/<path> with no credentials, query or fragment, and a Member is a relative path, so the two cannot change places. Blueprint.lock records the one SHA-256 of what a download's URLs serve, so an alternate need not be trusted.

A download that has a URL, and so can have alternates.

Workflows reference declarations; argv contains literal extra arguments.

Which package set a source is. Auto, which left that to the consumer, was removed in 0.6: the tag remains for one release so that lowering can say what to write instead.

A tool is written <source>#<name> for a declared source, in Tools, ToolsFor, Command and ToolWith alike. Tools and Overlays occur at most once. ToolsFor occurs at most once per System. Extend inherits tools and overlays parent first; an omitted or empty list does not clear inherited values. Command exposes one tool's main program under another name and may repeat with distinct names; the tool's own executables are not added. A child replaces an inherited Command of the same name. ToolWith adds a tool built with options its package takes, as names and values: data, never an expression. It may repeat with distinct tools, a child replaces an inherited tool's options, and a tool is either plain or configured, not both. RocPackages occurs at most once and lists released Roc bundle URLs to lock, so Roc programs in the environment resolve them without downloading; an extending environment inherits them. Programs occurs at most once and lists the fetched programs the environment has. Expect occurs at most once and names programs the machine must already have on PATH: they are checked for, never installed, and no version is asked of them. Both inherit parent first, and one name is only one of a program, an expected tool and a Command.

A shell is an alias for exactly one environment.

Tasks require exactly one Use and one nonempty argv Run.

Builds require Use, Run and one relative Output. Optional Inputs select locked non-flake Sources; Needs selects build artifacts, not task names. Sources and artifacts remain separate read-only inputs, never merged.